Food packaging material having uniform coating of oil

ABSTRACT

The present invention relates to a food packaging material for packing food, more particularly to a food packaging material having a uniform coating of oil, a method of manufacturing the same, and a mold for manufacturing the same. The food packaging material includes a plurality of grooves formed on one surface of the food packaging material; and an oil layer uniformly applied to the one surface of the food packaging material, being put into the grooves. According to the present invention, there are provided a food packaging material which continuously maintains a uniform coating of oil and thus minimizes sticking of contents to a surface of the packaging material, a method of manufacturing the same, and a mold for manufacturing the same.

CROSS-REFERENCE TO RELATED APPLICATIONS

This application is continuation application of U.S. application Ser.No. 15/384,733 filed Dec. 20, 2016, which is a divisional application ofU.S. application Ser. No. 14/344,215, filed Mar. 11, 2014, which is anational stage of International Application No. PCT/KR2011/008064, filedOct. 27, 2011, which claims the benefit of priority to KoreanApplication No. 10-2011-0095170, filed Sep. 21, 2011, in the KoreanIntellectual Property Office. All disclosures of the document(s) namedabove are incorporated herein by reference.

BACKGROUND OF THE INVENTION 1. Field of the Invention

The present invention relates to a food packaging material for packingfood, more particularly to a food packaging material having a uniformcoating of oil, a method of manufacturing the same, and a mold formanufacturing the same.

2. Description of the Related Art

Food packaging materials are used to package food. Food packagingmaterials have been improved to enhance stability of food storage,whereas a problem that contents stick to a food packaging material isnot solved.

For example, as to a food packaging material used as a top of aspoonable fermented milk product, when a consumer buys a fermented milkproduct and pulls the food packaging material, some contents stick tothe food packaging material. In this case, consumers mostly give up thecontents on the packaging material. The same problem occurs with respectto a food packaging material for packaging high-viscosity retort food,such as retort curry.

FIG. 1 illustrates a conventional food packaging material. In order tosolve the above problem, there is a try at coating the surface of a foodpackaging material 10 with edible oil.

In this case, however, as shown in FIG. 1, force caused by surfaceextension of oil acts in arrow directions, so that the edible oil formsa plurality of agglomerated oil drops 20. When the edible oil is notuniformly applied, contents are not prevented from sticking to thepackaging material.

SUMMARY OF THE INVENTION Technical Problem

The present invention is directed to solve problems mentioned above andprovides a food packaging material which continuously maintains auniform coating of oil and thus minimizes sticking of contents to asurface of the packaging material, a method of manufacturing the same,and a mold for manufacturing the same.

Solution to Problem

In accordance with an aspect of the present invention, a method ofmanufacturing a food packaging material having a uniform coating of oilincludes (a) preparing a mold including a plurality of prism bodies and(b) forming a plurality of grooves on one surface of a food packagingmaterial corresponding to the prism bodies by pressing the mold to thefood packaging material.

The method may further include (c) applying an oil layer to the onesurface of the food packaging material on which the grooves are formed.

The preparing the mold (a) may include (a-1) preparing a first metallayer, (a-2) depositing a photoresist layer on the first metal layer,(a-3) forming a plurality of pho-toresist holes disposed atpredetermined intervals by patterning the photoresist layer, and (a-4)forming the prism bodies on the first metal layer.

The photoresist holes may have a cylindrical shape or a polygonal prismshape and are arranged in a grid pattern.

The prism bodies may be formed on the first metal layer bygalvanoplasty.

The prism bodies may be formed on the first metal layer disposed in thephotoresist holes.

The first metal layer may be deposited on a silicon layer disposed underthe first metal layer.

The first metal layer may include titanium.

The prism bodies may include nickel or gold.

In accordance with another aspect of the present invention, a mold formanufacturing a food packaging material having a uniform coating of oilincludes a first metal layer, a photoresist layer formed on the firstmetal layer and including a plurality of photoresist holes disposed atpredetermined intervals, and a plurality of prism bodies formed on thefirst metal layer disposed in the photoresist holes.

The prism bodies may have a cylindrical shape or a polygonal prism shapeand are arranged in a grid pattern.

The first metal layer may be deposited on a silicon layer disposed underthe first metal layer.

The first metal layer may include titanium.

The prism bodies may include nickel or gold.

In accordance with still another aspect of the present invention, a foodpackaging material having a uniform coating of oil to package foodincludes a plurality of grooves formed on one surface of the foodpackaging material and an oil layer uniformly applied to the one surfaceof the food packaging material, being put into the grooves.

The grooves may be arranged at predetermined intervals in a gridpattern.

The grooves may have a cylindrical shape or a polygonal prism shape.

Advantageous Effects of Invention

As described above, the present invention provides a food packagingmaterial which continuously maintains a uniform coating of oil and thusminimizes sticking of contents to a surface of the packaging material, amethod of manufacturing the same, and a mold for manufacturing the same.

BRIEF DESCRIPTION OF THE DRAWINGS

These and/or other aspects and advantages of the invention will becomeapparent and more readily appreciated from the following description ofthe embodiments, taken in conjunction with the accompanying drawings ofwhich:

FIG. 1 illustrates a conventional food packaging material;

FIG. 2a is a perspective view of a food packaging material having auniform coating of oil according to an exemplary embodiment of thepresent invention;

FIG. 2b is a cross-sectional view of the food packaging material of FIG.2, taken along line A2-B2;

FIGS. 3a to 3d illustrate a method of manufacturing the food packagingmaterial of FIG. 2; and

FIGS. 4a to 7b illustrate a process of manufacturing a mold used in amethod of manufacturing a food packaging material.

DETAILED DESCRIPTION OF THE EMBODIMENTS

Reference will now be made in detail to exemplary embodiments of thepresent invention, examples of which are illustrated in the accompanyingdrawings. The embodiments are described below in order to explain thepresent invention by referring to the figures. This invention may,however, be embodied in many different forms and should not be construedas limited to the exemplary embodiments set forth herein.

Rather, these embodiments are provided so that this disclosure will bethorough and complete, and will fully convey the scope of the inventionto those skilled in the art. Description of unnecessary parts orelements may be omitted for clarity and conciseness, and like referencenumerals in the drawings refer to like elements.

Hereinafter, a food packaging material having a uniform coating of oil,a method of manufacturing the same, and a mold for manufacturing thesame according to exemplary embodiments of the present invention will bedescribed with reference to the accompanying drawings.

FIG. 2a is a perspective view of a food packaging material having auniform coating of oil according to an exemplary embodiment of thepresent invention, and FIG. 2b is a cross-sectional view of the foodpackaging material of FIG. 2, taken along line A2-B2.

Referring to FIGS. 2a and 2b , the food packaging material having theuniform coating of oil (hereinafter, “food packaging material”) 100according to the exemplary embodiment of the present invention is usedto package food, for example, used as a top for a fermented milk productor a packaging material for retort food. The food packaging material 100includes a plurality of grooves 110 which are formed on one side thereoffor a uniform coating of oil and an oil layer 120.

The grooves 110 may be formed in a minute size by microelectromechanicalsystems (MEMS), which will be described in detail.

The oil layer 120 is applied to a surface of the food packaging material100 having the grooves 110 in order to prevent food from sticking to thesurface of the food packaging material 100.

In particular, the oil layer 120 is put into the respective grooves 110to relieve force due to surface tension of oil, described with referenceto FIG. 1, and thus the oil layer 120 is not separately dispersed asagglomerated oil drops but is uniformed applied.

Further, as compared with the packaging material of FIG. 1, a coating ofthe oil layer 120 is stably maintained for a long time, and the oillayer 120 in the grooves 110 functions to push water or food, so thatthe food does not stick to the packaging material. Accordingly, aminimum amount of food sticks to the packaging material.

Also, the uniformly applied oil layer 120 prevents the food packagingmaterial 100 from being in direct contact with food, thereby avoidingharmful effects transmitted from the food packaging 100.

Here, the grooves 101 may be arranged at predetermined intervals in agrid pattern in order to uniformly form the oil layer 120, shown in FIG.2 a.

Further, the grooves 110 may have a cylindrical shape or variouspolygonal prism shapes, such as a triangular prism, a rectangular prism,a hexagonal prism, etc., and may have the same height.

FIGS. 3a to 3d illustrate a method of manufacturing the food packagingmaterial of FIG. 2 a.

Referring to FIGS. 3a to 3d , the method of manufacturing the foodpackaging material according to the present embodiment includes (a)preparing a mold and (b) forming grooves, and may further include (c)applying an oil layer.

Referring to FIG. 3a , in the preparing the mold (a), a mold 200 havinga plurality of prism bodies 210 and a food packaging material 100 areprepared.

Here, the grooves 110 are not yet formed in the food packaging material100, which is formed of synthetic resins, such as polypropylene (PP) andpolyethylene terephthalate (PET).

Further, the prism bodies 210 are provided to form the grooves 110 andformed in a corresponding shape to the grooves 110. Thus, the prismbodies 210 may have a cylindrical or polygonal prism shape and bearranged in a grid pattern.

Referring to FIG. 3b , in the forming the grooves (b), the foodpackaging material 100 and the mold 200 are arranged, and then the mold200 is pressed to the food packaging material 100, thereby forming aplurality of grooves 110 on one surface of the food packaging material100 corresponding to the prism bodies 210.

That is, when the mold 200 is joined to the food packaging material 100using heat and pressure, parts of the food packaging material 100corresponding to the prism bodies 210 are pressed by the prism bodies210, thereby forming the grooves 110.

These grooves 110 are formed based on a shape of the prism bodies 210.Thus, when the prism bodies 210 have a cylindrical shape, the grooves110 are formed in a cylindrical shape. When the prism bodies 210 have apolygonal prism shape, the grooves 110 are formed in a polygonal prismshape.

Referring to FIGS. 3c and 3d , in the applying the oil layer (c), themold 200 bonded to the food packaging material 100 is removed, and thenthe oil layer 120 is applied to the one surface of the food packagingmaterial 100 on which the grooves 110 are formed.

FIGS. 4a to 7b illustrate a process of manufacturing a mold used in amethod of manufacturing a food packaging material. With reference toFIGS. 4a to 7b , the method of manufacturing the food packaging materialis described in detail.

According to an exemplary embodiment of the present invention, (a)preparing a mold includes (a-1) preparing a first metal layer, (a-2)depositing a photoresist layer, (a-3) forming photoresist holes, and(a-4) forming prism bodies.

FIG. 4a illustrates the preparing the first metal layer (a-1), and FIG.4b is a cross-sectional view of FIG. 4a , taken along line A4-B4.

Referring to FIGS. 4a and 4b , in the preparing the first metal layer(a-1), a silicon layer 300 is prepared, and a first metal 310 is formedon the silicon layer 300.

Here, The first metal layer 310 may be formed on a silicon layer 300 inorder to uniformly form the first metal layer 310.

Further, the first metal layer 310 may include titanium and may alsoinclude other metals.

FIG. 5a illustrates the depositing the photoresist layer (a-2), and FIG.5b is a cross-sectional view of FIG. 5a , taken along line A5-B5.

Referring to FIGS. 5a and 5b , in the depositing the photoresist layer(a-2), a pho-toresist layer 320 is deposited on the first metal layer310.

Here, the photoresist layer 320 may include a positive photoresist or anegative pho-toresist. For example, AZ9260 may be used as a positivephotoresist, and SU-8 may be used as a negative photoresist.

FIG. 6a illustrates the forming the photoresist holes (a-3), and FIG. 6bis a cross-sectional view of FIG. 6a , taken along line A6-B6.

Referring to FIGS. 6a and 6b , in the forming the photoresist holes(a-3), the pho-toresist layer 320 deposited on the first metal layer 310is patterned. Thus, a plurality of photoresist holes 330 disposed atpredetermined intervals are formed in the photoresist layer 320.

That is, the photoresist holes 330 may be formed in the photoresistlayer 320 by exposing and developing processes of photolithography.

Here, the photoresist holes 330 may have a cylindrical shape or apolygonal prism shape and be arranged in a grid pattern. The first metallayer 310 under the photoresist holes 330 is exposed to the outside.

FIG. 7a illustrates the forming the prism bodies (a-4), and FIG. 7b is across-sectional view of FIG. 7a , taken along line A7-B7.

Referring to FIGS. 7a and 7b , in the forming the prism bodies (a-4),prism bodies 210 are formed in the photoresist holes 330. As the firstmetal layer 310 is exposed to the outside through the photoresist holes330, the prism bodies 210 are formed on the first metal layer 310. Thus,the mold 200 including the prism bodies 210 is completely formed.

Here, the prism bodies 210 may be formed by galvanoplasty. Thus, theprism bodies 210 may be formed on the first metal layer 310 and disposedin the photoresist holes 300.

In this case, since the photoresist layer 320 is nonconductive, theprism bodies 210 of a metal material grows only on the first metal layer310 having conductivity.

To this end, the prism bodies 210 may be formed of nickel (Ni) or gold(Au) or may also include other metals.

Using MEMS, a plurality of prism bodies 210 having a considerably minutesize may be formed on the mold 200, and accordingly the food packagingmaterial 100 may also be formed with considerably minute grooves 110.

The mold 200 to manufacture the food packaging material according to theembodiment of the present invention may be manufactured by the abovedescribed process, and thus the mold 200 includes the first metal layer310, the photoresist layer 320, and the prism bodies 210 (see FIGS. 7aand 7b ).

The first metal layer 310 may be formed on a silicon layer 300, and thephotoresist layer 320 having the plurality of photoresist holes 330 isdisposed on the first metal layer 310.

The prism bodies 210 are formed on the first metal layer 310 disposed inthe pho-toresist holes 330 to be exposed to the outside.

The mold 200 thus manufactured facilitates formation of the minutegrooves 110 in the food packaging material 100, so that each foodpackaging material 100 is not involved in a complicated processincluding photolithography. Thus, costs, time, and labor force involvedin manufacture may be reduced.

Although the spirit of the present invention was described in detailwith reference to the preferred embodiments, it should be understoodthat the embodiments are provided only for explaining the presentinvention and the present invention is not limited thereto. Further, itshould be understood that the present invention may be modified invarious ways by those skilled in the art, without departing from thescope of the present invention. The scope of the present inventiondescribed above is determined by the following claims and not limited tothe detailed description described herein, and equivalent changes andmodifications within claims are included in the spirit and scope of thepresent invention.

What is claimed is:
 1. A food packaging material having a uniformcoating of oil to package food, the food packaging material comprising:a plurality of grooves formed on one surface of the food packagingmaterial; and an oil layer uniformly applied to the one surface of thefood packaging material, being put into the grooves.
 2. The foodpackaging material of claim 6, wherein the grooves are arranged atpredetermined intervals in a grid pattern.
 3. The food packagingmaterial of claim 6, wherein the grooves have a cylindrical shape or apolygonal prism shape.